In order to reduce storage bitcosts, there is an increasing need for technology that reduces data volume. On the one hand, data compression technologies are known as technologies for reducing data volume. On the other hand, capacity virtualization technologies are known as technologies for reducing the capacity used in data storage. Capacity virtualization technologies show a host apparatus or the like, which exists outside of a storage system, a virtual capacity that is larger than a physical storage capacity capable of being used by the storage system.
In Patent Literature 1, a data compression technology and a capacity virtualization technology are used to dynamically allocate a storage destination area inside a pool to compressed data in accordance with the post-compression data size thereof. This enables Patent Literature 1 to increase storage capacity utilization efficiency. In addition, Patent Literature 1 does away with the need for a user to prepare a volume of a size that corresponds to the post-compression data size, thereby enhancing usability.